ROLLS:
So - it's nice you have a 'long roll' sample, but I find I'm having to generate my own rolls from single snare hits in most cases. There are some things about the rolls that would make it more usable.

1) It's hard to get a loud roll. Setting midi-velocity and audio volume to max does not have much effect. Would be great if the midi velocity had more effect like it does on the snare hits.
2) Sample(s) for buzz rolls and open rolls (the one provided sounds open which is fine).
3) The sample has a 'beginning accent' and an ragged end. Would probably be better if it was consistent. This would help with (4).
4) The sample has a fixed length. So if you need a longer roll, you need to concatenate them. But (3) makes this awkward. It might be nice if Play would somehow know how to 'extended' the roll to the length of the midi-note (might be easier if the sample didn't have the (3) behavior.

CYMBAL BELLS:
Would be nice if there were two at different pitches. (e.g. bells for the crashes as well as the ride). Hi-Hat bell (back of stick) also nice.

RIM CLICK: Would be a useful add.

OTHER COMMON CYMBALS: Splash, China, gong

Other percussion used with or around drum kits (possibly in other packages but ideally should be also here - perhaps as a separate kit): cow bell, wood block, egg shaker, tambourine, bar chimes.

I can't remember which kit (although it may be in the Joe Chiccarelli library, can't remember right now) has some brushes selection when you open the drums menu and swap out different drums.

Thanks C4L88, I'll check that out. My post was directed more towards the developers, but your input is most welcome. I probably should check out more of the kit and swap options before I make too many comments on the samples. Hopefully I can get back with some more feed back once I've worked through the cover I'm working on right now. Athough I'm still learning much, I'm finding I can get pretty close to the sound I want.

Perhaps I will ask a related question though maybe this should be a different thread:

Right now I'm just using one instrument track for the whole kit in Protools (actually there are two kits and two tracks - it's an Allman brothers tune!). While I'm tracking - it seems easier to just have the whole kit in one track (new to Protools too so haven't gotten into grouping tracks and such). But I can see during mixing, I'll probably want the kit split out into multiple tracks. However, it seems that when you add MIDI tracks to the instrument track for a multi-timbral instrument, you can't have plug ins on the MIDI tracks which effectively prevents you from doing independent FX processing on each unit apart from basic track automation (velocity, audio volume, etc.). Just as an example - maybe I want some phasing on the cymbals but not on the rest of the kit. I was thinking I would go ahead and finish tracking, then split the kit out as multiple tracks (Instrument/Midi) by just copying each part into the MIDI tracks, and then when I go to mix, print the tracks to audio and import them into a new session as audio tracks so then I could use plug-ins on independent parts. Does this make sense - or am I missing some easier path.

Not 100% on how you do this in Pro Tools, but in Logic you can set up a Multi-Output version of Play and achieve these results much more easily than the method you're describing. If you follow these basic instructions and adjust for the sake of Pro Tools' way of working, this should get you where you want to be.

Essentially, set up a Multi-Output instance of Play, load up your kit and go into the Mixer window. You should see the mic positions tab - three little faders on a button next to M, S, and FX. Now, under each instrument (Kick, for example) you should see "Output" set to "Default". You can change that routing to a variety of options. What you do now is set up audio tracks in Pro Tools that have the inputs routed from the outputs you've manually selected in the Play Mixer microphones window.

Hope that gives you a starting point. Not a major Pro Tools user here so I can't be totally specific in the step-by-step.